clockdrv_shell.h: Fix warning
Add -std=gnu++11 to CXXFLAGS if SMP is enabled

This is necessary to use the <atomic> header file used for the atomic
operations.
score: More strict RTEMS_DEQUALIFY implementation.

This implementation is able to catch cast to type
which differs not only in qualifiers. The error
diagnostic message when used in function is self
descriptive. Macro is compatible with used in initializers
but there message about not constant initial value
signals types incompatibility.

The actual implementation does not distinguish between
volatile and const removal.
tests: Rework interrupt critical tests

This avoids test durations of more than one hour on fast targets, since
fast targets can count a lot during one clock tick period, so the minor
loop iteration count was quite high.  Estimate now the test body
duration to iterate only through the interesting time window.

Add and use interrupt_critical_section_test().
bsp/qoriq: Fix tm27 support
psxtests/psxonce01: Use test extension
sptests/sp39: Convert to sptests/spintrcritical21

Use interrupt critical section test support.  Do not print end of test
message in case of failure.
arm/lpc176x: Adding "eth" linker script section.